Re: quantum nos.

I also wanted to know for a long time

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.''God exists because Mathematics is consistent, and the devil exists because we cannot prove it'I'm not crazy, my mother had me tested.

Re: quantum nos.

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.''God exists because Mathematics is consistent, and the devil exists because we cannot prove it'I'm not crazy, my mother had me tested.

Re: quantum nos.

And if I remember correctly, l can take values 0 to n-1.

Last edited by anonimnystefy (2013-12-03 05:15:57)

Here lies the reader who will never open this book. He is forever dead.Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and PunishmentThe knowledge of some things as a function of age is a delta function.

By the way, do you have an idea of what is there in the ICSE syllabus for Class X physics?

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.''God exists because Mathematics is consistent, and the devil exists because we cannot prove it'I'm not crazy, my mother had me tested.

Here's what I think, but it may all be wrong so believe me at your peril:

Electrons are not like miniature planets orbiting a nucleus. And 'shells' don't really exist as there is a non zero probability that an electron could be at any distance from a nucleus.

But let's pretend shells do exist because I cannot finish this without.

Electrons can only be at certain discrete energy levels. That's what 'quantum' means.

The principle quantum number tells you how many energy levels or shells an atom may have. It is given the letter 'n' and n can only be 1, 2, 3 etc.

The secondary quantum number is also known as the angular momentum or azimunthal Q.N. It is denoted by the letter 'l'.

l may take the value 0, 1 2, 3 .... up to n-1.

Letters are also used for these as follows: s=0, p=1, d= 2, f= 3, g= 4, h= 5 etc.

The reason for this choice of letters dates back to the time when scientists were first doing experiments to determine the nature of the atom. Spectra were described as sharp, principal, diffuse, and fundamental, and later these terms were applied to the secondary quantum numbers.

After fundamental, alphabetical order is used for subsequent letters. In practice, examples in nature rarely get much further up the list.

They are also referred to as sub-shells. But note what I said above about shells.

In theory, the behaviour of electrons can be determined from a function called an atomic orbital. In practice it may only be possible to obtain an approximation. The n and l values are the result of this calculation. Just to make things even more complicated there are two more characteristics that come from this: the magnetic Q.N. which can take integer values from -l to +l; and the spin Q.N. which can only take values of +½ or -½.

It is widely claimed that for a given atom no two electrons may have exactly the same Q.N.s Professor Brian Cox says that no two electrons in the entire universe may have the same energy state as any other! http://physics.stackexchange.com/questi … -electrons In this series of exchanges, no poster actually says he watched the programme, but I did, and I can confirm that he did say this. I think he may be occupying a different universe from the rest of us however as there are many reasons why this cannot be so. As he is widely acknowledged as an expert on this in the UK, it just goes to show the truth of the Feynman quote.

If you're still reading at this point, well done. I got lost several paragraphs ago.

If you're studying this topic and can shed any light ( photons ? ) that will help us make sense of Q. Mechanics then please post away.

Bob

Last edited by bob bundy (2013-12-05 02:08:40)

Children are not defined by school ...........The FonzYou cannot teach a man anything; you can only help him find it within himself..........Galileo Galilei

Re: quantum nos.

Hi Bob

I'd say that is the current standard.

In previous physics lessons we learned also that the electron energy levels of an atom in a molecule are split up into sublevels because of the forces in the molecules and the fact that electrons interact with other nuclei as well as their own.

Here lies the reader who will never open this book. He is forever dead.Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and PunishmentThe knowledge of some things as a function of age is a delta function.

Re: quantum nos.

bob bundy wrote:

I am amazed. I was expecting a flood of corrections.

well,i am just a novice on quantum mechanics and your article on it was as always understandable and satisfactory for me right now.I wanted to know the basics and i got it.thank you.Will surely add more to it when I get to know it more next year.

Re: quantum nos.

Nikharika, I may be wrong but I don't think they cover quantum numbers in the CBSE 10th standard curricula. A forum you can try, even though there are several science enthusiasts on here, is physicsforums.com. Agnishom, I have seen from the syllabus that the ICSE curricula is more rigorous then CBSE. I checked around meritnation for the content and to me it seems quite similar. Optics, basic Classical Mechanics and I think there was some EM.

Re: quantum nos.

Hi Bob

I have only one correction -- h=5*.

Here lies the reader who will never open this book. He is forever dead.Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and PunishmentThe knowledge of some things as a function of age is a delta function.

Re: quantum nos.

Thanks for explaining.

Shivam: Do you have an idea about where ICSE books can be downloaded from

'And fun? If maths is fun, then getting a tooth extraction is fun. A viral infection is fun. Rabies shots are fun.''God exists because Mathematics is consistent, and the devil exists because we cannot prove it'I'm not crazy, my mother had me tested.

Re: quantum nos.

Agnishom wrote:

Thanks for explaining.

Shivam: Do you have an idea about where ICSE books can be downloaded from

Unfortunately I couldn't find any downloadable online version of those books. But, I think you can safely assume that they are pretty similar to NCERT. By the end of 12th, you have pretty much covered the same material from CBSE, CISCE and the state boards.

Re: quantum nos.

Re: quantum nos.

Also, because I did not see Bob mention it, the magnetic Q.N. describes the direction of angular momentum.

Here lies the reader who will never open this book. He is forever dead.Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and PunishmentThe knowledge of some things as a function of age is a delta function.

Re: quantum nos.

Re: quantum nos.

Why is it weird that people have various interests?

Here lies the reader who will never open this book. He is forever dead.Taking a new step, uttering a new word, is what people fear most. ― Fyodor Dostoyevsky, Crime and PunishmentThe knowledge of some things as a function of age is a delta function.